Propeller or the like



H. FAEHRIVIANN. PROPELLER OR THE LIKE. APPLICATION FILED AUG.2. 191a.

Patented Oct. 12, 1920.

3 SHEETSSHEET I.

A TTOR/VEY.

H. FAEHRMANN. PH'OPELLER OR THE LIKE. APPLICAIION FILED AUG.2. 19w

Patented Oct; 122, 19205 3 SHEETS-SHEET 2.

INVENTOR.

I I d Z? A Y TORNEY.

1V1 TNESS:

H. FAEHRMANN PROPELLER OR THE LIKE. APPLICATION FILED AUG.2. I918.

Patented Oct. 12, 1920.

' 3 SHEETS-SHEET 3. 297? 35 WITNESS; 7 I INVENTOR.

A TTORNE Y.

HERMANN FAEHRMANN', or BROOKLYN, NEW YORK.

PROPELLER OR THE LIKE.

To all whom it may concern Be it known that I, HERMANN FAEHRMANN,

a citizen of the United States, and resident" I it is particularlyapplicable for use with aeroplanes, where high speeds are required.

Propellers at the presenttime are commonly formed of wood, which is, ofcourse, curved to acertain pitch. In a propeller of this character thecentrifugal forces which act radially from the shaft tend to strightenout the blade, while the forces resulting from the air pressure tend tobend back the blade, it is possible to attain with safety with this typeof propeller is limited to a-value below that which it is desirable'inpractice to secure, and, at best, the propeller blades are frequentlybroken because of thestrains set upby these forces. f

In accordance .with my invention, the propeller blade'comprises 'anumber of support ing ribs which constitute the frame-work for theblade,and Which 'eXtend radially outwardly from the shaft or hub .in thesamedirections' as do the centrifugal forces resulting from the rotationof the ribs, so that there is not only no tendency-for the ribs tobecome distorted because of these forces but the forces so set upactually provide-the means to resist the tendency of the blade to becomefiat, In accordance with my invention, also, the ribs-are as to'withstand the enormous strains to I which they .are subjected becauseof such forces.- Y I I Another object of my invention is the provision.of means .fordetachably securing blade unit to the hub. Other featuresof my invention will appear from the specification, and will be moreparticul'arly' pointed out in the claims.

My invention will best Figure 1 hub and shaft, ribs mounted thereon. v

Specification of Letters latent.

. Fig. 5.

with the result that the speed which Fig; 16 is an end .View so. formedbe understood by referenceto the accompanying drawings, in which-' I isa longitudinal section of a. with the inner ends of 'Ithe.

' Patented Oct- 12, 1920.

Application filed August 2, 1918. Serial No 247,915. I I

Fig. 2 is a vertical section on the line 22 of Fig. 1.

Fig. 3 is a top plan view of this form of my nvention, with parts insection.

Flg. 1 is a cross-section ,onthe line H of Fig. l. a

Fig. 5 is a cross-section similar to Fig. 2, illustrating a modificationof the previous form. I

Fig. 6 is a .section on the line 6-6 of Fig. 7 is a'partial section ofthe same character as Fig. l, but showing the'form of my inventionillustrated in Figs. 5 and'6.

Fig. 8 is an end view of a propeller embodying the preferred form of. myinvention, in

which the propeller blades are balanced against each other, and'hereshowing two propeller blades mounted diametrically I opposite each otheron the shaft.

, Fig. 9 is a side view of Fig. 8.

Fig. 10 is a longitudinal'section through the hub and associated parts'and showing ,v I

parts in side elevation. 4

Fig. 11 is a sectional View showingjthe preferred arrangement forsecuring the inner ends of the -clamping rings. I

' Fig. '12 is a sectionaI elevation on the line .12-12 of Fig. 8. Fig.13 is a sectional view. on the line 13- 13 of Fig. 8. I I I Fig. 14: isaview similar-to Fig. 13 but. showing a covering on both sides of theblade."u I

Fig. 15-is an end view of a blade removed from the hub,.andshowingcovering plates or webs secured to the ribs; I 4

I of one of the ribs. Fig. 171's a side view of the same. I Fig. 18 isaview similar to Fig. 17 but showingthe finger formed on its inner end.extending in the opposite direct on,

rib somewhat exaggerated to illustrate better the invention, and

blades in position between and l showing the taper in the thickness ofthe Fig. 19 isan end view of threeequally' I spaced blades secured-tothe propeller shaft.

In the form of my invention shown in Figs. 17 the -propeller shaft. is.-provided with 'asingle blade, suitable means being I provided forcounterbalancing the same. The. propeller blade is mounted on ashaft 10,the end of which is tapered as at 11, and the eXtreme' end of which isscrew-1 v shoulder 16 which engages a corresponding shoulder 17 of thehub. The end of the hub is preferably formed with a cap 18 which isprovided with a central screw-threaded opening 19, which engages thescrew-threads 12 on the end of the shaft. The cap is secured to the hubsection lat by screws and nuts 20, 21 respectively, suitablev recessespreferably being formed in the hub to re ceive the same. Ribs 22,constituting the supporting frame-work for the blade, are

v secured between the rings 15 and the hub width and in thickness forthe purpose of from the inner toward were not so reduced in size andmass.

.be rotated at higher speeds hub remote from the blade sections,suitable recesses 28 being provided between the hub sections and thevarious rings for the reception ofthe ribs. The ribsare tapered towardtheir outer ends and may be tapered in either width or thickness, butare preferably tapered both in giving them a form which enables them towithstand the strains to which they are subj ected,'beca-use of thecentrifugal forces.- The velocity of the outer ends of the ribs is, ofcourse, much greater than that of the inner ends, and as the centrifugalforces 'of a given rib rise with the square of the velocity i the outerend, it is of the greatest importance that the outer ends of the ribsshould be less in cross-section than the inner ends. A rib so formedprovides the largest cross-section near the shaft or hub, where it iscalled upon to, resist the greatest strains. the mass at the outer endciently reduced to enable of the rib is sufiithe propeller to than havehitherto been attained and at higher speed than would be possible if theends of the e inner ends of the ribs are preferably provided withfin'gers'23, which are received in recessesQ l formed on the inner facesof the rings 15, so that the fingers are secured in position between therings and the shaft.

egistering openings 25 and 26 are preferably provided in the hubsections 13 and 14, which register with corresponding openings 27 formedin the rings 15, the opening as a whole being disposed on the side ofthe hub adjacent to the blade. The side of the is, accordingly, heavierthan the other side and acts as a counterbalance to the blade. web 29 issecured to the ribs, and in the form shown in Fig. 2 this web iscomposed of a single piece secured to the ribs by, rivets 30. The web ispreferably secured to the ribs away from the hub, so that the ribs maybe sprung apart and permit of the insertion or removal of the innerretaining rings 15 At the same time,

A plate or of the hub.

which are received between the rings, are

in assembling or disassembling the propeller.

The hub sections 13 and 14: are preferably secured to the adjacent ringsby pins 31.

In the form of my invention shownvin Figs. 5, 6 and 7 the ribs areformed integrally with rings 32, which are secured to a shaft 10 whichis here shown as square in cross-section. The plate which is secured tothe ribs is also shown as formed of three separate sections, 29, 29 and29", a section being secured to each two adjacent ribs. Each blade unitis preferably made insections, as shown in Figs. 5, 6 and 7, so that ablade unit may readily be detached from the hub and a section removedtherefrom in order to make repairs.

.The preferred form of my invention is shown in Figs. 8 to 18, in whichthe propeller blades are so mounted on the shaft as tocounterbalanceeach other; that is, two

propeller blades may be mounted diametri tiple thereof may be employed.In ,one embodiment of my invention the propeller blades, which I haveindicated in general by the character A, are mounted on a hub 33 ofknown form, which is secured to the shaft 10. The hub is provided withan end flange 34, the opposite end of the hub being closed by a clampingmember 35, which is also formed with an outwardly extending flange 34and has a cylindrical portionsurrounding the body portion ofthe hubproper. Annular rings 1:? are mounted on the hub and are clamped inposition by a member here shown as a screw-threaded clamping ring 36,which engages the flange 34 and which is received on a screw-threadedpart on the hub. A screw-threaded cap 38 is preferably provided to coverthe end of the shaft. The ribs 22 are received-in radial openings 15formed inannular raised sections 15 formed in the faces of the rings.The innerends of the ribs are preferably formed with fingers 2.3" bentat right angles to the main portions of the ribs, the fingers beingreceived between the rings and the hub. I have here shown the fingers oneach of the outer ribs extending outwardly, the fingers on theintermediate ribs extending in the same direction as that of one of theouter ribs. It is to be understood, however, that all of the fingers,includingboth of those of the outer ribs, may extend in the samedirection, though I prefer the first construction, as it enables me toreduce the thickness of that intermediate ring which is adjacent to therib whose finger is turned in the direction opposite to that of the others, and correspondingly decrease the weight The inner 'ends of theribs,

, metal securedon one face ofthe ribs.

preferably rectangular in cross-section, and formed with plane surfaces,in order the better to secure the ribs in position, theribs being curvedor twisted without the rings, as best shown in Fig. 8, in order toobtain the desired pitch. I have shown in Figs. 8

and 9 three separate plates or webs 29 29 formed (if and 29?, which arepreferably isto be understood, however, that a greater or lesser numberof ribs and correspondlng covering'plates may be used without depart-1ing from my invention.

*The ribin the direction of advance of the propeller is preferably thecarries the greatest strains,

longest, since it the ribs decreas in gin length to the other edge ofthe blade.;

The outer ends of the long plates with the long ribs. also'have thesmallest pitch, the pitch gradually increasing toward the small bladeswith the short ribs.

The provision of ribs, in accordance with my invent on, which outer endsis of the utmost importance, since it permits of the propeller beingrevolved at a highs speed than it has hitherto been:

possible to attain. The strains developed in straight'ribs at higherrevolutions would be of such great magnitude as to break the propeller,Curved-ribs would be impracticable, sincethe centrifugal force wouldstraighten the ribs when run at high speed. The provision of the taperin the ribs is, therefore,

a feature of much greater importance than might at first blush appear,since this feature makes the'form of propeller embodying myinventioncommercially practicable.

In Figs. 9,10'and'11 I have shown the section of the hub securedtogetherby suitablebolts 4:0.

In' some cases both faces of the blade with plates or webs inorder toincrease the efliciency of the same and to add to the general appearanceof the blade. I'have shown'such a modification in Fig. 14:, in whichseparate blade sections 41 and 42 are secured to the faces of the ribs."Furthermore, it is to be understood that a covering of a material suchas fabric or the like may be applied to either or both faces of theblades.

In accordance with my invention, the various blade units may separatelybe detached from the hub "on which they are mounted. This feature is ofimportance.

-ing the cap clamping-ring 36. The bolts are then taper toward their Ifind itdesirable to coveras 18 ordinarily the case where two the hr(referring particularly to Fig. 10), the hub and the blades securedthereto are demounted from the shaft by first remov- 38 and thescrew-threaded removed and the flange 34 taken off. The annular rings 15may then be removed by varied by theuse of washersof differingthicknesses.

spreading the ribs 22 and a single blade What I claim 'and desire tosecure by Letters Patent of theUnited States is 1. A structure adaptedfor use-asa propeller or for other purposes, comprising'a shaft, a hubbody-and hubrings fitted on said shaft, ribs extending inwardly betweensaid-rings and provided withfeet extending between the shaft andthe-said rings, ablade secured to said ribs, and

.holding the hub body and they hub rings on said I shafts.

- 2. A structure adapted for use as a propeller or for other purposes,comprising a shaft, a-hub body andhub ringsfittedon said shaft andprovided with recesses in their adjacent faces, ribs extending inmeansfor wardlywithin said recesses and provided Y with feet extendingbetween the shaft -aiidtlle said-rings, a web secured to said ribs, andmeans for holding the hub bodya'nd the hub rings on said shaft.

35A structure adapted for use as a propeller or for-other purposescomprising a shaft, a'hub body thereon, ribs extending into said hubbody and provided with'rings fitted on the shaft, and a web secured tothe outer portions of said ribs.

4. Apropeller comprising, a hub adapted to'be secured to a shaft, ablade comprising a. plurality of ribs, and annular spacing ringssurrounding said hub for spacing said ribs longitudinally ofthe hub andsecuring the same thereto.

5'. A propeller comprising a hub adapted to be secured to' a shaft, ablade comprising a plurality of ribs formed at their inner of ribsadapted to be secured at their inner ends to the hub, and a coveringsecured to the ribs away from their inner ends, and means for securingsaid unit to the hub constructed and arranged to permit detachment ofthe unit from the hub without'removing 1 said covering from said ribs.

-7 A high-speed propeller, comprising a pluralit of bladescounterbalanced against each ot er, each blade comprising a plurality ofmetal ribs extending from the hub in straight lines, and eachrib beingwider in its plane of rotation than at right angles thereto and taperinguniformly both in width and thickness "from the hub of the propeller tothe end of the rib, the ribs of each blade beingprogressively shorterfrom one edge of the blade to the other edge of the blade, and acovering connected to the ribs and conforming approximately on its outeredge'to the lengths of the successive ribs.

8. A high speed propeller, comprising a plurality of bladescounterbalanced against each other, eachblade comprisinga plurality. ofmetal ribs extending from the hub in straight lines, and each ribbeing'wider in its plane ot' rotation than at right angles thereto andtapering uniformly both inwidth and thickness from the hub of thepropeller to the endof the rib, the ribsof each blade.

being progressively shorter from the leadin edge of the blade to therear of the blade, and a covering connected to the ribs and conformingapproximately on its outer edge to the lengths of the successive ribs.

9. A high speed propeller, compris ng a plurality of bladescounterbalanced against each other, each blade comprising a plurality ofmetal ribs extending from the hub in straight lines, and each rib beingWider in its plane of rotation than at right angles thereto and taperinguniformly both in width and thickness from the hub of the propeller tothe end of the rib, the ribs of each. blade being progressively shorterfrom the leading edge of the blade to the rear of the blade, and theribs of each blade bein spaced along the hub with the longestri towardthe front of the hub, and a covering connected to' the ribs andconforming ap-' proximately on its outer edge to the lengths of thesuccessive ribs.

10. A high-speed propeller comprising a plurality of metal ribsextending outwardly from the hub in straight lines at their cen ters,each rib being Wider in its plane of rotation than at right anglesthereto, one

J OHN W. PAnKIN W. B. PHILPOTT.

